Soil Health Indicator | Soil Function | Scoring Curve Type |
|---|---|---|
Measure every: 1-3 years | ||
ACE Soil Protein | Nutrient cycling, biodiversity & habitat, filtering & resilience | More is better |
Aggregate Stability | Physical support, water relations, biodiversity & habitat, filtering & resilience | More is better |
Electrical Conductivity (EC) | Physical support, nutrient cycling, filtering & resilience | Less is better |
Mineralizable Carbon | Nutrient cycling, biodiversity & habitat, filtering & resilience | More is better |
Permanganate Oxidizable Carbon (POXC) | Biodiversity & habitat, nutrient cycling, filtering & resilience | More is better |
Potentially Mineralizable Nitrogen (PMN) | Nutrient cycling, biodiversity & habitat, filtering & resilience | More is better |
Soil pH | Nutrient cycling, filtering & resilience | Optimal range |
Total Nitrogen | Nutrient cycling, biodiversity & habitat, filtering & resilience | Optimal range |
Plant Essential Nutrients | Nutrient cycling | Optimal range |
Measure every: 3-5 years | ||
Bulk Density | Physical support, water relations, biodiversity & habitat, filtering & resilience | Optimal range |
Cation Exchange Capacity | Nutrient cycling, filtering & resilience | More is better |
Infiltration | Water relations, physical support | More is better |
Soil Organic Matter (SOM) | Nutrient cycling, filtering & resilience | More is better |
Water Holding Capacity (WHC) | Water relations, physical support | More is better |
Results from Test Project
Fall 2023
Test Project
Example of a project summary
Soil Health
Soil health is a term that describes how well a soil ecosystem supports plants, animals, and humans. It also recognizes the living nature of soils and the importance of soil microorganisms. Healthy soils can provide wildlife habitat, support biodiversity, reduce the effects of climate change, filter air and water, increase crop productivity and food security, and ensure thriving rural economies.
Soil Science 101
A crucial part of the soil health journey is measuring changes in your soil and understanding how to interpret those measurements. We can measure soil health with a range of indicators describing a soil’s physical, chemical, and biological properties, which can relate to important soil functions. Each indicator measures a different property of the soil and can be affected differently by management.
To learn more about management practices that support healthy soil, check out these resources from the Natural Resources Conservation Service (NRCS) principles of building soil health.
What We Measured in Your Soil
Soil Texture is the relative proportion of sand, silt, and clay-sized particles in your soil. Imagine these particles like basketballs, golf balls, and poppy seeds, which are very different in size even though soil particles don’t appear different to the naked eye. Importantly, soil texture describes only the mineral portion of the soil and is not affected by organic matter or management. However, soil texture is a significant driver of how soils respond to management. Soils with higher clay content can hold more nutrients, organic matter, and water than sandy soils. This is because clay particles have high surface area and electrical charge and create small soil pores. Soils with high sand content have larger pores, and cannot hold as much water.
Bulk Density is the mass of particles within a certain volume of soil and is used as an indicator of soil compaction. Bulk density varies depending on soil texture and structure and is greatly affected by tillage, tractor passes, and organic matter inputs. It is a primary determinant of soil aeration, porosity, water infiltration, and root growth. For more information on the special equipment required to measure bulk density, consult this NRCS protocol.
Soil pH describes how acidic (pH less than 7.0) or alkaline (pH greater than 7.0) the soil is, and is a measure of the concentration of hydrogen ions in the soil solution. Many essential nutrients like P, Fe, Mn, Zn, Cu, Co, and B become less plant-available at alkaline pHs. Other nutrients like Al or B can become toxic at acidic pHs. Soil pH also greatly affects what microbial populations can live in the soil. Soil pH is impacted by inherent qualities of the soil such as its age, mineralogy, and rainfall zone. It is also impacted by fertilization, irrigation water pH, and SOM content. Most agricultural crops grow best in neutral soil pHs, within a range of 6 to 8. Soil pH can be lowered using sulfur or raised by adding agricultural lime.
Total Nitrogen is a measurement of both inorganic (plant-available nitrate and ammonium) and organic (typically not plant-available) nitrogen in the soil. Having sufficient total nitrogen in the soil is key for promoting mineralization, or the process of changing the organic nitrogen to a form that plants can use.
Soil Health Indicators
The below table describes: 1. What each indicator helps measure in your soil; 2. Whether you want the measured value to be higher (more is better), lower (less is better), or in the middle (optimal range); and 3. How often to measure each indicator. Our understanding of these indicators is rapidly evolving as researchers measure them in diverse soils, cropping systems, and climates.
Soil Health Testing
Looking Forward
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